Urban Investment and Development Co., the Chicago development firm that built Water Tower Place, 845 N. Michigan Ave., in 1976 and was acquired by JMB late last year, owns the other half of the commercial areas.

The Water Tower Place deal was closed in March, although final details weren`t disclosed until Wednesday.

The transaction didn`t include the project`s Ritz Carlton Hotel, which is owned separately and operated by the Four Seasons Hotel Group of Toronto, according to Norman Perlmutter, chairman of Heitman Financial.

Nor did the deal include the condominiums in the 74-story tower, where units are owned by individuals, and common areas, by their condo association, Perlmutter said.

``Water Tower Place is probably the premier mixed-use property in the U.S., if not the world,`` Perlmutter said. ``We plan to hold it for a long time.``

Water Tower Place`s commercial areas consist of an eight-story, 602,000-square-foot shopping mall, including Marshall Field and Lord & Taylor department stores; 140,000 square feet of offices on two floors above the mall; and the 667-car parking garage beneath the building, Perlmutter said.

Heitman Advisory bought into the project on behalf of the HAC Group Trust, a closed-end, commingled fund for pension fund investors; and a major pension fund account that Perlmutter declined to identify. A JMB spokesman said the purchase was for the syndicator`s own account.

Perlmutter said the partners paid cash for the building, but he declined to say how much.

A rough idea of the magnitude of the transaction can be obtained from public records in the Cook County assessor`s office. The assessor recently assigned the property an assessed valuation of $40.5 million. This will be the basis for calculating the building`s real estate taxes.

Because commercial building assessments equal 40 percent of market value, the $40.5 million figure means the assessor pegs Water Tower Place`s value at $101.3 million.

The assessor ranks Water Tower Place as the most valuable property on the Near North Side after the Merchandise Mart, which was reassessed at $40.8 million and is estimated to have a market value of nearly $102 million.

JMB is one of the nation`s largest syndicators, having raised more than $2.1 billion for public and private limited partnerships since its founding in 1969.

JMB is a joint venture partner with Metropolitan Structures in 3 Illinois Center, Boulevard Towers North and the Chicago Mercantile Exchange complex at 10 and 30 S. Wacker Dr.

Through Urban, the syndicator has a stake in the 333 W. Wacker Dr. and 200 S. Wacker Dr. office towers. Urban also is constructing a $350 million office, hotel, retail and residential complex, patterned after Water Tower Place and to be anchored by the city`s first Bloomingdale`s department store, at 900 N. Michigan Ave.